Bobbin construction



April 1967 M. SCAGLIA BOBBIN CONSTRUCTION 2 Sheets-Sheet 1 Filed June 2,1965 April 25, 1967 M. SCAGLIA BOBBIN CONSTRUCTION 2 Sheets-Sheet 2Filed June 2, 1965 United States Patent Oflice 3,315,916 Patented Apr.25, 1967 BOBBIN CBNSTRUCTIGN Mario Scaglia, Bergamo, Italy, assignor toM. Scaglia S.p.A., Bergamo, Italy Filed June 2, 1965, Ser. No. 460,698Claims priority, application Italy, July 6, 1964,

10 Claims. (Cl. 242-118.6)

This invention relates to improvements in the construction of bobbins ofthe type adapted for having yarn wound thereon. In particular, the yarnis of the kind spun from man-made fibers.

The general form of construction of the bobbin includes a tube with endflanges mounted on the tube. When yarn is wound on such a bobbin, theyarn exerts a lateral force on the flanges tending to displace theflanges off the tube. If an opening or fissure should be formed in thejoint between the adjacent surfaces of the flanges and tube, it ispossible to snag the yarn in such fissure which will result in breakagein the yarn when it is unwound from the bobbin.

It is an object of the invention to provide an attachment between theflanges and the tube, in which there will be virtually no possibility ofthe formation of a fissure or opening between the flanges and the tubeduring Winding of the yarn whereby the danger of snagging yarn issubstantially completely eliminated.

It is a further object of the invention to provide an improved methodand means for securing the flanges to the tube such that the flanges arepro-stressed in a manner to resist the formation of fissures or openingsbetween the flanges and tube.

Yet another object of the invention is to provide means for elasticallyand adjustably controlling the magnitude of such pro-stressing.Heretofore a substantially cylindrical metallic tube was employedwhereon the yarn is wound, and both ends of the tube are upset andupturned against related flanges, which are thereby secured on the tubeparallel with each other and thus perpendicular to the tube axis. Theflanges can be made of a suitable material such as plastic, Bakelite,metal, or the like. The flanges must be adequately secured on the bobbintube to prevent the formation of fissures or openings between the innersurfaces of the flanges and the outer surface of the tube when thebobbin is being wound with the related yarn. In particular, since yarnsspun from manmade fibers can be wound under strong tension, highstresses are exerted by the yarn being wound, both in a radial directionon the tube and in a lateral direction against the flanges. This resultsin bending stresses in both flanges, tending to deflect the flangesoutwardly off their seats at both tube ends. As a direct consequencethereof, spaces are formed between the flanges and the tube, and theyarn may be engaged thereinto under strong tension, whereby when suchbobbins are to be unwound, yarn breakages and the like are experienced.

Known arrangements which have attempted to overcome the above have beenbased partly on improvements in the strength and stiffness of theconnection between the flanges and tube and partly on the provision ofmechanical means to prevent the formation of said spaces. Otherarrangements include means to fill such spaces simultaneously with theirformation, in such a manner as to insure continuity of the surfaces onwhich the yarn is wound. Many of the above-stated known arrangementshave been presented in patents by the applicant. Such arrangements havenot proven to be entirely satisfactory.

The present invention, however, is directed to an entirely novelconcept.

In this respect, the invention is characterized by the provision of asuitable elastic pre-stressing which is produced by suitable means, in adirect or indirect way, in each flange, which is fitted in a relatedseat in the tube. In other words, a system of inwardly directed internalstresses is produced in each flange to thereby counteract and resist thelaterally applied outwardly directed stresses which are produced whenthe yarn is being wound on the bobbin.

The above characteristic feature of the invention can he obviouslycarried into effect in different practical forms, both as regards themeans for producing said elastic pro-stresses, and the shape,arrangement and construction of said means, as well as the number andlocation of such means with respect both to the flanges and to thebobbin tube.

According to a first embodiment of this invention, the means forproducing said elastic pre-stresses in the flanges, comprises at leastone elastic ring seated in a suitable annular groove that extends in agenerally radial plane extending substantially perpendicular to the tubeaxis, in the inner peripheral wall of each flange, said annular groovebeing delimitated all along its base by the outer cylindrical surface ofthe tube which constitutes a seat for the flange. The end of the tube isupset and upturned against the flange to firmly secure it to said tube.By the presence of at least one groove of the abovestated type, theaxial elasticity of the flange is considerably increased, whereby, whenthe tube end is upturned against the flange in order to secure it tosaid tube, the elastic ring previously seated in said groove is squeezedand thus exerts a given elastic pressure which is transmitted in alldirec tions against the groove wall and particularly in the requiredaxially inwards directed sense. Stated otherwise, the inside wall of thegroove will be pro-stressed in an inwards direction of the bobbin,whereby the flange is forced to elastically engage the tube seat at agiven elastic stress, which will preferably always be greater than theoutwardly directed stress exerted on the yarn while it is being woundunder strong tension on the bobbin. This will prevent the flange frombeing displaced out of its seat and off the bobbin, as well as theformation of spaces or fissures in which yarn can be engaged.

According to another embodiment, the means for producing the inwardiydirected elastic stress, advantageously consists of only one or moreofthe above: annular grooves without the insertion of an elastic ring.Such grooves increase the axial elasticity of the flange, which as aconsequence of the upsetting and upturning of the end of the bobbintube, will generate the required elastic pre-stress.

In yet another embodiment such means may comprise a spring member whichelastically engages each flange and applies an inward elasticpre-stress, which tends to elastically maintain the initial position ofthe flange on the tube seat.

Said spring member may be a spiral spring, a cup-shaped spring, a flatspring, or the like, which may be adjustable to vary the magnitude ofpro-stress exerted on the flanges.

To additionally improve the locking action by which the flanges areretained in their seats on the tube, and to positively prevent theminute displacement of such flanges, with the consequent formation offissures and spaces, the tube seat is defined as an annular recess inthe outer surface of the tube, with an outwardly inclined inner face.Such inclined face cooperates with a mating portion of the flange wallin such a manner that contact between said two walls will always beestablished at the outer cylindrical surface of the tube for allmagnitudes of stress to which the flange is subjected.

The above and further objects, features and advantages of this inventionwill become more apparent fromthe following description taken with theaccompanying drawing showing a number of embodiments of the inventiongiven by way of non-restrictive example. In the drawing:

FIGURE 1 is a side view, partly in section, of a bobbin wherein theflanges thereof are secured to the tube according to a first embodimentof the invention;

FIGURE 2 is an enlarged view of a detail of one end of the bobbin ofFIG. 1;

FIGURE 3 is an enlarged axial section of the end of a bobbin, showing asecond embodiment of the invention;

FIGURE 4 is an enlarged view, partly in section, of the end of a bobbin,showing a third embodiment of the invention;

FIGURE 5 shows partly in axial section, a plastic plug and integralsleeve which is adapted for insertion into an end of the bobbin tube;and

FIGURE 6 is a cross-section of the plug and a bush as taken along lineVIVI of FIG. 5.

Referring now to the drawing, and in particular to FIGS. 1 and 2thereof, therein is shown a bobbin assembly A which is particularlyadapted to accommodate yarn spun from man-made fibers, and which, asalready well known, consists of a metal tube B having side flanges Cslipped over both ends of the tube. The flanges C are secured on thetube B in a manner which will be described in more detail later on. Suchbasic structure of the bobin is completed by a pair of plastic plugs 10,forced into the bore 12 of the bobbin tube, with a plastic tube insert14 clamped between both plugs and two bushes 16 in the plugs 10. Suchbushes preferably are constituted of bakelized fabric.

As well known, the yarn (not shown) is wound on the cylindrical surface18 of the tube B, which therefore must be joined, without interruption,with the inner annular sides 20 of flanges C, against which the yarncomes to rest. The wound diameter of the yarn is usually equal todiameter d of the flanges C. As already known, while the yarn is beingwound, a double system of forces is produced, of which one, acting inthe direction of the arrows X, is not detrimental to the structuralintegrity of the bobbin assembly, since it is resisted by the tubeitself. The other force system acts in the direction of arrows Y andwill be hereinafter referred to as lateral stresses. Such lateralstresses act to drive the flanges longitudinally of the central tube B,causing the flanges C to creep in the direction of arrows Y against thereaction forces which are generated by the means by which the flangesare locked to the tube. Theoretically, it may be conceived that eachflange, under the action of its own system of lateral stresses, will bebent outwardly around the corresponding end D of the bobbin tube. Due tothe above-stated bending stress, the sides 20 tend to deflect away fromthe surface 18 at the surface joints 22, 24, which would produce spacesbetween surfaces 18 and 20. Such deflection is detrimental to theoperational reliability of the bobbin, since the yarn can be snagged insuch spaces, with consequent breakage of yarn and lack of serviceabilityof the bobbin.

In the embodiments shown in FIGS. 1 and 2, there is provided meansadapted to exert elastic action to produce elastic stresses designed toresist and overcome the lateral stresses acting in the direction ofarrows Y. Such means comprises a groove F cut in the inner periphery ofeach flange C, and an elatic ring M seated in the groove F, be-- forethe flange is forced over the tube. Each flange is, formed with a boreby which it can he slipped over the corresponding end D of tube B, andis locked therein by the engagement of said flange C into the seat Hthat is formed on the end D, as well as by the upsetting and up turningof end portion 26 of the metal tube against the corresponding flange.The upturned portion 26 in cooperation with the conical section 28 ofthe flange, will result in the production of compression stress exertedon the flanges and bobbin in the direction of the arrow Z, and thus in afirm securing of flange C in seat H.

Obviously, the above construction described for the left flange isappropriate also for the right flange.

While in FIG. 1 the groove F is shown wholly filled A. by the ring M, inFIG. 2 the same groove appears to be only partly filled by said ring.This is the case because FIG. 2 represents an intermediate stage ofinstallation, the metal edge 26 being not yet fully upturned and pressedagainst the cone portion 28 of the flange, as in FIG. 1.

As shown in the drawing, the ring M becomes wholly enclosed within thebobbin, i.e., in the groove F thereof, and thus is enclosed andprotected against any external action which would tend to causepremature wear thereof.

The ring M in the groove F exerts an elastic action on the flange C,whereby a system of elastic stresses is produced within the flange. Thestresses of the latter system are designed to act in opposition to thelateral forces which act on the flanges in the direction of arrows Y. Infact, when the edge 26 is upturned against the flange C, the side wallsof groove F, by which the axial resilience of said flange is materiallyincreased, are drawn nearer by a given amount, depending on the forceexerted by said edge 26, whereby the material of elastic ring M isdeformed in both radial and axial directions, thus filling the entirespace of the thus deformed groove F. As a consequence thereof, the ringM will exert an elastic force on the flange C and in particular on thewalls 11, 13 of such flange, since said elastic ring tends to resume itsinitial shape and because the elastic limit of both the flange and thering M is never exceeded when the metal edge 26 is upturned. Thereby, aforce is exerted by the ring on both walls 11, 13, whereby a force isexerted in an axial or lateral direction opposite to Z on the wall 11and in the direction of Z on wall 13. It is the latter force that iseffective for the purpose of always maintaining continuity between theouter surface 18 of the tube and the side surfaces 20 of the flanges.The abovestated elastic action is permanently exerted, due both to thetendency of ring M to resume its initial shape and also of groove F toreturn to its initial form. Such elastic action constitutes a pre-stresshaving the function of counteracting the lateral stress produced by thewinding of yarn acting in the direction of arrows Y. Such prestress mustalways exceed, at least by a small amount, the stresses that are to beresisted, whereby the wall 20 is permanently kept in contact with thesurface 15 of seat H, thus preventing the existence of objectionablespaces between the flanges and the tube, and thereby eliminating thepossibility that the yarn can be caught therein.

As can be seen in FIG. 2, the wall 15 of the seat H that is formed onthe tube D, is conveniently inclined outwardly, thus having a coneshape. The wall 17 of flange C is adjacent wall 15 and is inclined withrespect thereto. Thus, wall 17 may be inclined or may be perpendicularto the tube B. As can be seen in the drawing, the recess in the tubedefining the seat H, is bounded by the above wall 15, and the walls 15,17 come into contact with each other after the edge 26 has been upturnedagainst the flange C. The inclination of said walls 15, 17 is a furthercontribution to a positive prevention of the existence of spaces atsurfaces 22, 24. In this respect the force Y exerted by the winding ofthe yarn, tends to bend the flange C outwardly around a rotation center19, in the direction of arrow V, and the wall 17 attempts to moveupwards by sliding along the wall 15, and out of the seat H. As aconsequence of such sliding motion, a fissure-like void would be formedbetween the surface 18 of the tube B and the surfaces 20 of the flangesC. Such formation of a void is prevented by the fact that contact isalways maintained between the walls 15 and 17 as a consequence of theirrelative inclination.

It is possible to use one or more grooves F 'without the elastic ringsM, as a means to exert the elastic action by which the requiredpre-stressing of flanges C is produced. In such a case said grooves areleft empty. As can be readily appreciated, the local resilience of theflange C is increased by the pressure of such grooves, whereby anelastic action is exerted for counteracting the stress Y exerted by theyarn.

A further embodiment is shown in FIG. 3 for bobbin A. In more detail theflange C, which is engaged as usual by its section G in the seat H ofthe bobbin tube, is elastically acted upon by a cup-shaped spring N thatit slipped over the end D of tube B. The edge 26 of said end D of tube Bis upset and upturned against the spring N, in order to produce therequired elastic action in the direction of the arrow Z, and by whichthe flange C is elastically pre-stressed, thereby to counteract and toovercome the above-stated lateral stresses Y exerted by the yarn.

In this latter case, only the wall 15 of seat H is inclined, while thewall 17 of the flange is straight and perpendicular to the bobbin axis.

In the third embodiment of bobbin A", as shown in FIG. 4, the means bywhich the flange C is connected with the tube B, comprises a spiralspring P that is slipped over a pin 21 which is secured to tube B andwhich projects beyond the flange C. The elastic load that is exerted inthe direction of the arrow Z on flange C can be properly adjusted bymeans of a nut 23, that is screwed on a threaded end of said pin 21 andby which the spring P can be more or less compressed by the washer 25.The compression of the spring constitutes an elastic load thatcounteracts and overcomes the stress exerted by the yarn winding, whichtends to drive the flange off the tube.

In all cases as considered above, the magnitude of the elasticpre-stress that is directly or indirectly applied to the flange C, canbe adjusted when assembling the bobbin. Amongst others, the limit valueof pre-stressing to be imparted to flanges C in the case of theembodiment in FIGS. 1 and 2, is defined by the increase in theresistance that is opposed by the elastic ring M while being graduallydeformed in its groove F as a consequence of upsetting and upturning theedge 26 of tube B. Thus, the ring M acts also as an indicator of themagnitude of pro-stressing that is imparted to the flange, whereby themagnitude can therefore be visually adjusted according to requirements.

Even in the embodiment of FIG. 3, the elastic force exerted by thespring N can be adjusted according to requirements by adjusting thedegree of upsetting and upturning of the edge 26. The same can be saidwith regard to the embodiment in FIG. 4, wherein the elastic action canalso be adjusted by varying the degree of threaded engagement of the nut23 on its threaded pin.

Referring now to FIGS. 5 and 6, there is shown a plastic plug which issecured with a related bush 16 for being inserted into the metal tube Bby forcing them as an assembly through the inwardly projecting rims atthe seats H in the tube ends C. Thus said plug is required to be highlyresilient to allow it to be forced through said rims, the diameter ofwhich is smaller than the plug diameter 27.

For the above purpose, a plurality of ribs 29 are advantageouslyprovided in the plug. Such ribs extend in an intervening space 31,between an inner cylindrical hub 33 that is locked on the relatedcylindrical surface of bush 16 and an outer cylindrical wall 35 that isadapted to be inserted into the metal tube B. All the ribs 29 extendtangentially from hub 33, which is an important feature of theinvention, since said arrangement results in a material increase in theradial resilience of plug 10.

In fact, when the assembly of plug 10 and bush 16 is inserted into therelated end opening of bobbin tube B, the edge 27 is deformed andnarrowed to pass through the end D, such deformation being facilitatedby the presence of ribs 29 which are readily deformed under the stressapplied to the cylindrical wall 35. After the plug 10 has reached itsfinal position, wherein said rim at the end D of the tube becomesengaged in the groove 37, the tangential ribs 29 will resume theirnormal shape, thereby bringing the cylindrical wall 35 into contact withthe associated wall of bobbin tube B, and therefore each plug 10, onreaching its final position, wholly accommo- 6 dates itself within theinside shape of the related section of bobbin tube B.

The increase in the elasticity of plug 10, as required for attaining theabove purposes, cannot be attained when the ribs are not arranged in asubstantially tangential direction. Forexample, if the ribs are radiallyarranged, a much lower elasticy is obtained, since such ribs would beacted upon by a compression stress instead of a bending stress, therebyoffering a higher resistance to deforrnation.

While the invention has been described in detail, it is to be understoodthat the description is for the purpose of illustration only and is notdefinitive of the limits of the inventive concept. Numerous changes inthe details of construction and arrangement of parts will be apparent tothose skilled in the art within the scope and spirit of the invention asdefined in the attached claims.

What is claimed is:

1. A bobbin comprising a tube having an end, a flange constituted ofresilient material mounted on and encircling the tube at said end, saidtube and flange having abutting surfaces and forming a substantiallycontinuous uninterrupted surface for the accommodation of yarn to bewound on the bobbin, said tube having an annular recess of given radialdimension defining a seat for said flange, the abutting surface of thetube being a bounding surface of the recess, said tube including anupturned end portion at the remote end of said tube applied against theflange to urge the same in a direction away from the end of the tube tocause said abutting surfaces to be forced into contact with one another,said flange having an inner peripheral surface in facing relation withthe tube in said seat, said flange having an annular groove opening intosaid inner peripheral surface, said groove having a depth greater thanthe radial extent of the recess and providing axial elasticity for saidflange for the development of elastic pre-stress between the abuttingsurfaces with the upturned end portion applied against the flange.

2. A bobbin as claimed in claim 1 further comprising an elastic ringaccommodated in the groove of the flange.

3. A bobbin comprising a tube having an end, a flange constituted ofresilient material encircling the tube at said end, said tube having anannular recess of determinable radial extent constituting a seat inwhich is accommodated said flange, said flange having an innerperipheral surface facing said seat, said flange having oppositesurfaces, said recess being bounded by a surface remote from the end ofthe tube, which surface is in contact with the surface of the flangewhich faces away from said end of the tube, said flange being providedwith an annular groove which opens into the inner peripheral surface ofthe flange, said groove having a depth greater than the radial extent ofthe recess and providing axial elasticity for the flange at the level ofsaid groove, said tube including an upturned portion. at the extreme endof the tube in engagement with the other of the surfaces of the flangeand applying an adjustable force against the flange to elasticallydeform the peripheral groove therein which thereby develops a prescribedelastic pre-stress condition in the flange urging the surface thereofwhich faces away from the end of the tube against the aforementionedsurface of the tube which bounds said recess whereby the latter surfacesare forced into contact with one another with a predetermined magnitudeof prestress.

4. A bobbin as claimed in claim 3 com-prising an elastic ring in saidgroove also being subjected to elastic deformation by the application offorce to the flange by the upturned portion of the tube.

5. A bobbin as claimed in claim 3, wherein said groove has across-section which is inclined outwardly in a direction towards the endof the tube.

6. A bobbin as claimed in claim 3, wherein said bounding surface of therecess is inclined radially outwards in 7 1 direction towards the end ofthe tube, the surface of :he flange which is in contact with the lattersurface extending substantially perpendicular to the axis of the tube.

7. A bobbin as claimed in claim 3, wherein said flange has a conicalrecess in said other surface thereof for receiving the upturned portionof the tube.

*8. A bobbin comprising a tube having an end and an internal bore ofdeterminable diameter, a flange coupled to said tube at said end andhaving a surface in contact with a surface of the tube to form a jointthereat, means elastically acting on the flange to develop an elasticprestress therein which urges the surfaces of the tube and the flange atsaid joint into tight engagement to provide a substantially continuoussurface at said joint and prevent opening thereof, an insert in saidtube at said end closing the same, said insert comprising an assembly ofan elastic outer plug and inner bush inserted in said plug, said outerplug comprising an outer cylindrical wall, an inner cylindrical hubcoaxially within the wall in spaced relation, and a plurality of ribsextending between the hub and the wall, said ribs extending tangentiallyfrom the hub to the wall and providing substantial radial elasticitybetween the wall and the hub.

9. A bobbin as claimed in claim 8 wherein said outer cylindrical wall ofthe plug has a groove conforming to the shape of the seat foraccommodating the same, said wall in a region outside of said groovehaving an outer diameter exceeding the inner diameter of the tube atsaid seat.

10. A bobbin as claimed in claim 8 wherein said tube has an end oppositethe first said end and a second flange identical to the first coupled tothe tube at the second end, there being provided a second insert in saidtube at said second end, the bobbin further comprising an insert tubemember supported Within the tube and positioned between the inserts atthe opposite ends.

References Cited by the Examiner UNITED STATES PATENTS 634,738 10/1899Sampson 2421 18.6 1,150,011 8/1915 Barker 242-1186 1,395,038 10/1921Clinton 242-118.61 1,862,694 6/1932 McC-onnel et al. 242-1 18.61 X3,013,378 12/1961 Newton 242-1l8.6 X 3,081,960 3/1963 Howe 24273 XFOREIGN PATENTS 558,613 5/1923 France.

FRANK J. COHEN, Primary Examiner.

GEORGE F. MAUTZ, Examiner.

1. A BOBBIN COMPRISING A TUBE HAVING AN END, A FLANGE CONSTITUTED OFRESILIENT MATERIAL MOUNTED ON AND ENCIRCLING THE TUBE AT SAID END, SAIDTUBE AND FLANGE HAVING ABUTTING SURFACES AND FORMING A SUBSTANTIALLYCONTINUOUS UNINTERRUPTED SURFACE FOR THE ACCOMMODATION OF YARN TO BEWOUND ON THE BOBBIN, SAID TUBE HAVING AN ANNULAR RECESS OF GIVEN RADIALDIMENSION DEFINING A SEAT FOR SAID FLANGE, THE ABUTTING SURFACE OF THETUBE BEING A BOUNDING SURFACE OF THE RECESS, SAID TUBE INCLUDING ANUPTURNED END PORTION AT THE REMOTE END OF SAID TUBE APPLIED AGAINST THEFLANGE TO URGE THE SAME IN A DIRECTION AWAY FROM THE END OF THE TUBE TOCAUSE SAID ABUTTING SURFACES TO BE FORCED INTO CONTACT WITH ONE ANOTHER,SAID FLANGE HAVING AN INNER PERIPHERAL SURFACE IN FACING RELATION WITHTHE TUBE IN SAID SEAT, SAID FLANGE HAVING AN ANNULAR GROOVE OPENING INTOSAID INNER PERIPHERAL SURFACE, SAID GROOVE HAVING A DEPTH GREATER THANTHE RADIAL EXTENT OF THE RECESS AND PROVIDING AXIAL ELASTICITY FOR SAIDFLANGE FOR THE DEVELOPMENT OF ELASTIC PRE-STRESS BETWEEN THE ABUTTINGSURFACES WITH THE UPTURNED END PORTION APPLIED AGAINST THE FLANGE.